When he reached the room where they were still waiting, intent on attacking him, he caught sight of one of them by the light of the moon and immediately rushed in amongst them, saying: ‘You’re done for, you bastards! You came here seeking to harm me, but the tables are turned now. Here is Tristan who will bring sorrow on you!’
And he struck one of the knights so fiercely that in spite of his helmet Tristan split his head down to his teeth. The knight who felt himself mortally wounded staggered, and as he fell, he let out an anguished cry and said: 'Alas, I’m done for!’
When the others heard these words, they were so dismayed that they thought they were all done for, and many of them even
dropped their swords, they were so frightened. Tristan turned towards another who was making for the window and hit him so
hard that he cut off his entire left shoulder. And the knight fell to the ground, crying: ‘Alas, I’m done for!’

Prose Tristan